Diagnostic instrument



July 16, 1957 s, RODBARD 2,799,270

DIAGNOSTIC INSTRUMENT Filed April 25, 1955 2 Sheets-Sheet l 1 i l l 3755 5? 49 h iii" 2:551 25 @2 1 J y 1 19-57- I v I S. RQDBARD 2,799,270

DIAGNOSTIC INSTRUMENT I Filed April 25, 1955 I 2 Sheets-Sheet 2afimaola- 19 9144? United States Patent DIAGNOSTIC INSTRUMENTSimouRodbard, Chicago, Ill., assigno'r to Michael Reese ResearchFoundation, a non-profit corporation of Illinois Application Apr" 25,1955, Serial No. 503,444

14 Claims. (Cl. 128-'-2.05)

This invention relates to a diagnostic instrument combining thefunctions of a stethoscope and sphygmomanometer, and for conveniencewill be hereinafter referred to as a sphygmeter.

As is well known, a stethoscope is an instrument for auscultation and iswidely used in medical work. A simple stethoscope consists of a smallbell shaped member connected by flexible tubing to one or two ear piecesand adapted to transmit sounds generated at the bell. The technique ofusing a stethoscope varies among individual doctors and in some measuredepends upon the pressure of the bell upon the skin.

A sphygmomanometer is used for the measurement of blood pressure and thecommon form thereof includes a flexible air-tight bag with means forobtaining suitable air pressure within the bag and havingpressure-indicating means, such as a pressure gauge. Such an instrumentis relatively heavy and large in comparison to a conventionalstethoscope and in addition has several disadvantages. Thus the cuff orbag of the common sphygmomanometer directly contacts a large area ofskin and should therefore be sterilized after each use. This is not donein actual practice. In addition, the common type of sphygmomanometer canbe used to measure blood pressure and pulse pressure only at certainparts of the body, such as for example at the arms or legs.

An instrument embodying the present invention has the advantages of astethoscope and none of the disadvantag'es of a sphygmomanometer whilecombining the functions of both the stethoscope and sphygmomanometer. Aninstrument embodying the present invention makes it possible to functioneither as a stethoscope or sphygmomanometer in a manner superior to thefunctioning of conventional stethoscopes and sphygmomanometers.

The new instrument, designated as a sphygmeter, generally comprises astethoscope having means for applying a predetermined pressure to a skinarea.

For a complete understanding of the invention, reference will now bemade to the drawings wherein exemplary embodiments illustrative of theinvention are shown. It is understood, however, that variations andmodifications of the constructions illustrated may be made withoutdeparting from the scope of the invention except as defined by theappended claims.

Referring therefore to the drawings, Figure 1 shows a sphygmeterembodying the present invention;

Fig. 2 is an enlarged sectional view of the skin-contacting portion ofthe sphygmeter illustrated in Fig. 1;

Fig. 3 is an enlarged sectional view of the skin-contacting portion of amodified form of sphygmeter;

Fig. 4 is a sectional detail of the skin-contacting portion of a stillfurther modified form of sphygmeter;

Fig. 5 is a sectional elevation of the skin-contacting portion of anadditional modified form of sphygmeter;

Fig. 6 is a section on line 6-6 of Fig. 5, and

Fig. 7 is a sectional elevation of a still further modified form ofskin-contacting portion of a sphygmeter.

Referring first to Figs. 1 and 2, the sphygmeter comprisesskin-contacting and sound pick-up portion generally indicated by 10connected to tubular member 11. Tubular member 11 is connected to arigid Y 14, each branch of which is connected by flexible rubber tubes15 engages apertured portion 2,799,270 Patented July 16, 1957 and 16 tobent rigid tubular members 18 and 19. Tubular members 18 and 19terminate in ear pieces 20 and 21. Tubular members 18 and 19 are adaptedto be springpressed to the position illustrated in Fig. 1 by curvedspring 22 attached to tubular members 18 and 19. With theexception ofskin-contacting portion 10, the structure described is conventional andmay assume a variety of forms.

Referring now to Fig. 2, skin-contacting portion 10 is shown in enlargedform. Skin-contacting portion 10 has bell 25 having hemispherical cavity26 communicating with axial bore 27. Bell 25 may be of any suitablematerial, such as plastic or hard rubber, and is preferably of rigidmaterial. Bell 25 has threaded portion 28 and sleeve portion 29extending axially thereof, bore 27 being in part formed in the bodyofbell 25 and in threaded portion 28 and sleeve 29. p

Engaging threaded portion 28 of the bell is end 30" of plunger sleeve31. End 30 of the plunger sleeve is threaded so that the sleeve and bellmay be tightly joined. Plunger sleeve 31 has end'portion 32 enlarged toform a shoulder, the outer surface of the shoulder thus formed beingprovided with a series of annular slots 33 for accommodating packingrings.

Shouldered end 32 of the plunger sleeve works within cylinder 35 carriedby fitting 36. Fitting 36 and cylinder 35 may be of one piece orcylinder 35 may be of metal having a smooth inside surface while fitting36 may be of molded material. Cylinder 35 has outer edge 37 inwardlyturned to provide a locking lip so that enlarged shoulder 32 of thesliding plunger will be locked within the cylinder chamber. 7

Fitting 36 has nipple 37 disposed within the top end thereof. Nipple 37is tightly pressed into the fitting and V 38 of cylinder 35 to make anairtight fit which will withstand pressure. Nipple 37 has portion 40over which the rubber tube 11 may be disposed.

Nipple 37 has axial bore 42 into which is snugly fitted. tube 43. Tube43 is of rigid material and may, for example, be of brass, copper 'orany other suitable material.

Tube 43 in effect forms an extension for nipple 37, tube 43 extendingthrough fitting 36. Tube 43 has its outer surface finished smoothly andworks inside of sleeve 29 of the bell. The fit between the tube 43 andsleeve 29 should be air-tight. If desired, one or two annular grooves inthe outer surface of tube 43 or the inside surface of sleeve 29 or bothmay be provided for some small O-rings for the purpose of insuring anair-tight seal while permitting the two parts to slide relative to eachother.

Fitting 36 carries pressure gauge 48 of any suitable type, the gaugehaving air inlet 49 disposed in a recess within the fitting. Air inlet49 is connected to the interior of cylinder 35 by a channel so thatgauge 48 may indicate the air pressure existing within cylinder 35.

Fitting 36 is recessed to accommodate ball type check valve 50. Thecheck valve communicates with the in terior of cylinder 35 by channel51. Normally the spring pressed ball keeps the valve closed against anypressure build-up within the cylinder 35. However, in order to permitthe air within cylinder 35 to be equalized with atmosphere for gaugecalibration, the check valve may be opened by pressing a wire from theoutside against the ball bearing.

To use the device illustrated in Figs. 1 and 2, fitting 36 may begrasped by the hand and positioned so that bell 25 rests upon the skinof a patient. Fitting 36 is then pressed down toward bell 25 to forcethe bell against the skin, the telescoping arrangement serving toincrease the air pressure within cylinder 35. The air pressure will beindicated by the needle of gauge 48 while at the same time soundspresent within chamber 26 of the bell will be transmitted to the earpieces. Thus auscultation is possible while impressing bell 25 upon theblood vessels or skin at a predetermined pressure.

Referring to Fig. 3, a modified form of the apparatus is shown whereinexpansible bellows rather than sliding sleeves are utilized. Bell 25'has threaded portion 28 and flanged end 55. Inner expansible bellows 56has one end 57 spun or coiled around flange 55 to form an air-tightseal. Expansible bellows 56 may be of spring brass or copper or may evenbe of molded flexible rubber or plastic. Expansible bellows 56 has end59 provided with reduced nipple 60.

Threaded over portion 28 of the bell is end portion 60 of outerexpansible bellows 61. Bellows 61 is preferably of spring copper orbrass and is rigidly attached to fitting 36'. The inside of fitting 36'may be conveniently formed of bellows extension 62 having couplingfitting63 at the end thereof. Coupling fitting 63 is apertured toaccommodate nipple portion 60 of the inner bellows to provide anair-tight seal. Coupling fitting 63 is adapted to have rubber tube 11'slipped over the same.

Fitting 36' carries gauge 48, this gauge and the mounting thereof beinggenerally similar to the construction illustrated in Fig. 2. Thus gauge48 has air inlet aperture 49 connected to the interior of outer bellows61 through a restricted channel passing through the wall of fitting 36'and the wall of extension 62 of the outer belows.

In assembling the construction illustrated in Fig. 3, inner bellows 56may be attached to bell 25' prior to the insertion of the bellows withinouter bellows 61. Thereafter outer bellows 61 may be attached to hell25' by turning the entire fitting 36' and outer bellows with respect tothe bell. During the attachment of the outer bellows to hell 25', innerbellows 56 is retracted so that nipple 66 does not extend into theaperture in coupling fitting 63. When the two bellows are properlypositioned with respect to hell 25', a tool may be inserted from thebell end of the device up channel 27' in the bell and inside the innerbellows to engage the annular shoulder formed between extension 59 andnipple 60. Nipple 60 may then be forced into the channel in couplingfitting 63.

It will thus be clear that the contraction of outer bellows 61 willresult in increased air pressure being developed within the bellows,which increased air pressure will be indicated by gauge 48'. In order toeliminate any inaccuracy due to the spring in the two bellows, innerbellows 56 which has finer convolutions may be normally in a tensionedcondition so that in the position illustrated in Fig. 3, inner bellows56 has a tendency to contract. At the same time, outer bellows 61 may becontracted somewhat from a normal untensioned condition. Thus it ispossible to rely upon the natural spring of inner bellows 56 to increaseits length somewhat to overcome the resistance of outer bellows 61 tocontract due to the spring of the metal. When fitting 36' is grasped bythe hand and the bell is pressed upon the skin of the patient, the forceof the bell upon the skin will be indicated by the pressure gauge andthe reading thereof will be the true force exerted upon the bell byvirtue of the air compressed within outer bellows 61.

The construction illustrated in Fig. 3 is provided with check valve 50'similar to the construction shown in Fig. 2.

Instead of having outer bellows 61 as illustrated-in Fig. 3, a slidingsleeve arrangement as illustrated in Fig. 2 may be used. In such case,inner bellows 56 will take the place of thc telescoping tube arrangement29 and 43 of Fig. 2.

It is also possible to dispense with inner bellows 56 in themodification illustrated in Fig. 3 and instead use a pair of telescopingsleeves as illustrated in Fig. 2.

In the two modifications heretofore described, the pressure of the bellupon the skin has been due to compressed air within a sealed chamber,the pressure of the air being indicated by a gauge. It is possible toprovide a modification wherein the pressure of the bell upon the skin isdue to a compressive force upon a spring and the amount of pressure willbe indicated by the displacement of the spring from normal position.Referring to Fig. 4, bell has barrel 66 threaded over the same. Barrel66 has a number of graduations as indicated in the drawing. Barrel 66operates in cylinder 67 of fitting 68. The shouldered arrangementillustrated in Fig. 2 may be used in Fig. 4 to maintain barrel 66 within67 at the extreme retracted position of the barrel. Within cylinder 67is coil spring extending between top wall 71 of fitting 68 and thethreaded end of bell 65. Coil spring 70 tends to bias barrel 66downwardly as illustrated in Fig. 4. By holding fitting 68 and pressingbell 65 against the skin, compression of spring 70 will result in thebarrel being moved upwardly into the fitting. The compression of thespring will be indicated by the graduations on the barrel, suchgraduations being suitably calibrated so that readings may be duplicatedor may be referred to some standard air pressure.

The barrel and fitting may be made of metal or some rigid plastic. It isnot necessary, and in fact undesirable, that an air-tight seal beestablished between the barrel and the fitting. As illustrated in Fig.4, bell 65 has the usual axial channel providing an air path into theinterior of hell 66 and fitting 67. Wall 71 of fitting 67 is suitablyapertured to provide a through air path to the ear pieces of the device.

Referring now to Figs. 5 and 6, a further modification is illustratedwherein the air path for auscultation is distinct from thepressure-generating part of the device. In this modification, bell 75has body 76 containing cylinder 77 in which piston 78 is adapted tooperate. In order to prevent Withdrawal of the piston from the cylinder,body 76 may have lip 80. In practice, this lip may be formed by a metalliner for body 76 with the edge of the metal spun over if the piston isdisposed in position. However, other means such as a separate cover forcontaining the lip may be applied to body 76 after the piston isinserted.

Piston 78 is supported from handle portion 82 containing air pressuregauge 83 connected to the air chamber within cylinder 77 through bore84. Suitable packing for the piston may be provided to provide a tightair seal. An air check valve 85 is connected to bore 84 for,equalization purposes.

Body 76 has channel 86 extending through the same, channel 86 havingmouth 87 at the bell chamber. Body 76 has nipple extensions 88 forchannel 86 and over nip-. ple extension 88 rubber tube 89 may be drawn.The remainder of the instrument including the metal Y and the ear pieceswill follow along the lines illustrated in Fig. 1.

It is wherein subjected the entire area of skin underneath the bell isto a desired air provided from the bell chamber to the ear pieces. Thusreferring to Fig. 7, bell 90 has stem 91 provided with axial channel 92extending into bell chamber 93.

Branching from stem 91 is part 94 having bore 95 in,

communication with axial channel 92. Attached to part 94 by a slip fitor other means is rubber bulb 96 having air intake and exhaust valves 97and 98. Rubber bulb 96 may be squeezed and exhaust valve 98 will permit,compressed air from bulb 96 to pass into the tube and into the valvechamber.

The air pressure region is sealed by flexible diaphragm 100 maintainedin position by part 101 engaging the threaded end of 91 to clamp thediaphragm in position. Diaphragm 100 may be of thin steel or springbrass or phosphor-bronze or other resilient material strong enough toWithstand the desired pressure upon the skin while responding to thesound vibrations generated within the bell chamber. Nipple 102 of part101 may be enalso possible to have a sphygmeter construction pressure, asound path being.

gaged by rubber tube 103, the rubber tube going to the Y connection asabove.

It is also possible to modify Fig. 2, for example, by providing adiaphragm to seal the bottom end of the nipple 37. Thereafter, thetelescoping sleeve arrangement may be dispensed with and the increasedpressure within the cylinder will be communicated to the bell chamber.

Similarly, the modification illustrated in Fig. 3 may be changed byproviding a diaphragm to seal nipple 60 and dispensing with the innerbellows arrangement completely. In such cases, it will be necessary todesign the pressure-generating means so that suflicient pressure may begenerated Within the bell, this being accomplished by proper design ofthe piston stroke and piston displacement.

By virtue of the invention, auscultation technique may be greatlyimproved. The variations in pressure of a bell or diaphragm of astethoscope on the chest or other body parts may markedly affect theintensity and quality of tones heard. The new sphygmeter makes itpossible for auscultation to occur under known pressure conditions. Thusintensity and quality of sounds remain as the only parameters to bequalitatively assessed.

What is claimed is:

l. A sphygmeter comprising a bell for engaging a small skin area, meansfor exerting a measured pressure of the bell upon the skin engaged bythe bell, and means for providing an acoustic path from the bellinterior to the ears of an observer for auscultation.

2. A sphygmeter comprising a bell for engaging a small skin area, meansincluding a piston and cylinder for creating a measured pressure of thebell upon the skin, and means for providing a direct air path from thebell interior to the ears of an operator.

3. A sphygmeter comprising a bell for engaging a small skin area, ahandle portion for the bell, said handle portion including a sealed airchamber whose volume may be expanded or contracted to adjust the airpressure therein, means for indicating the air pressure so that saidbell presses upon the skin with predetermined force, and means forproviding an acoustic path from the vbell interior to the ears of anoperator.

4. A sphygmeter comprising a member having a bell body for engaging asmall skin area, a handle portion for holding said bell body against theskin, said handle portion being relatively movable to said bell body,piston and cylinder means disposed between said handle portion and bellbody so that said bell may be pressed upon the skin with desired force,means for indicating the pressure inside said cylinder and means forproviding an acoustic path from the bell interior to the ear of anoperator.

5. A sphygmeter comprising a bell for engaging a small skin area, ahandle portion for said bell, relatively movable cylinder and pistonmeans between said handle portion and bell so that said bell may bepressed down upon the skin through the operation of said piston andcylinder means, said cylinder being sealed, an air pressure gaugeconnected to the interior of said cylinder to indicate the pressurewithin said cylinder, a conduit extending from the interior of said bellthrough the piston and cylinder means and the handle and means forconducting sounds through said conduit to the ear of an operator.

6. A sphygmeter comprising a bell for engaging a small skin area, saidbell including a body portion having an air passage from the bellinterior to the exterior thereof, pressure-generating means connected tosaid passage for generating an air pressure within said bell interior, adiaphragm forming one of the walls of said air passage for confining theair under pressure while transmitting vibrations, and means forproviding a direct acoustic path from said diaphragm to the ear-of anoperator whereby said bell may be held in position on the skin with apredetermined air pressure impressed on the skin while providing forauscultation.

7. A sphygmeter comprising a bell having a body portion, means in saidbody portion for creating a measured air pressure within said bell, adiaphragm forming part of the air enclosure for the region within whichair is compressed, and means for providing a direct air path between thediaphragm and the ear of an operator.

8. A sphygmeter comprising a bell having an axial channel therethrough,a pair of concentric sleeves coaxial with said channel extending fromsaid bell, a member having a pair of coaxial sleeve surfaces forcooperating with the bell sleeve surfaces, the inner sleeve on saidmember and inner sleeve on said bell providing a sliding conduit forsounds from the bell interior through said member, the outer sleeve ofsaid member and outer sleeve of said bell cooperating to provide asealed air chamber whose volume may be varied to control the airpressure within said chamber, a pressure gauge carried by said memberand having a part communicating with the interior of said air chamberfor indicating air pressure and means for conveying the sound in saidinner sliding sleeve arrangement to the ears of an operator.

9. A sphygmeter comprising a bell having an axial channel therethrough,a pair of expansible bellows attached to said bell, said two bellowsbeing concentric, the inner bellows providing an extension for saidaxial channel, means coupled to said outer bellows for providing asealed air chamber around said inner bellows, pressure gauge means forindicating the pressure in the sealed air space and means for conductingthe sound transmitted through said inner bellows to the ears of anoperator.

10. The sphygmeter according to claim 9 wherein said two bellows areoppositely tensioned so that the tendency of one to contract issubstantially neutralized by the tendency of the other one to expand.

11. A sphygmeter comprising a bell having an axial channel therethrough,a pair of telescoping sleeve members carried by said bell, the interiorof said telescoping sleeve members communicating with said axialchannel, a spring in said telescoping sleeve members, means forindicating the compression of said spring due to telescoping one memberinto said other member and means for conducting the sound from saidtelescoping members to the ears of an operator.

12. A sphygmeter comprising a member having a concave region forming abell, a channel extending from the bell region through said member forconveying sound, means for transmitting the sound from said channel tothe ear of an operator, a second member, said two members havingcooperating portions providing a cylinder and piston arrangement, apressure gauge carried by said second member, said second member havinga channel extending from said pressure gauge into the cylinder of saidcylinder and piston arrangement so that said pressuge gauge may measurethe air pressure within said cylin er.

13. The construction according to claim 12 wherein a check valve isprovided, said check valve communicating with the interior of saidcylinder whereby the air within said cylinder may be equalized withatmosphere.

14. A sphygmeter comprising a member having a bellshaped region and anaxial channel, a pressure gauge carried by said member and communicatingwith said axial channel, an air pump connected to said axial channel forproviding air under pressure thereto, said air pump including a checkvalve and said axial channel including a diaphragm for maintaining theair pressure within said axial channel and bell at a desired value andmeans cooperating with said diaphragm for communicating sound to the earof an operator.

References Cited in the file of this patent FOREIGN PATENTS

